In recent years, for example, various apparatuses such as computers, e.g., a notebook PC (Personal Computer), or television receivers have more functions and apparatuses having a function of enabling wireless communication with other apparatuses have become widespread. Here, wireless communication between such apparatuses is performed, for example, using a carrier (electromagnetic waves) having a predetermined frequency, seen as a 5 GHz band.
Meanwhile, in recent years, technology for increasing a communication speed of wireless communication using a carrier having a higher frequency than a millimeter wave has been developed. Here, the millimeter wave refers to, for example, a carrier having a wavelength of 10 mm to 1 mm and a frequency of 30 GHz to 300 GHz. Accordingly, for example, when a millimeter wave such as a 60 GHz band carrier is used for communication, channels can be allocated in units of GHz such that the communication speed can be higher compared to the case in which a 5 GHz band earner is used for communication.
In general, a millimeter wave such as the 60 GHz hand carrier has a characteristic in that the millimeter wave has a stronger directivity or a greater attenuation resulting from reflection than the 5 GHz band carrier. Thereby, communication using the millimeter wave such as the 60 GHz band carrier is mainly performed using a direct wave or a once-reflected wave. The millimeter wave such as the 60 GHz hand carrier has a further characteristic in that the millimeter wave has a higher free space propagation loss than the 5 GHz band carrier. Accordingly, in general, the communication using the millimeter wave has a shorter communication distance than communication using the 5 GHz band carrier.
Meanwhile, technology related to communication using a carrier having directivity has been developed. Technology of providing three or more antennas having different set directivities and selectively processing any signal received by each antenna may include, for example, Patent Literature 1.